Monday, 5 May 2014

Installing Windows Server 8

Every small business with five or more employees should use a server/client based infrastructure to utilise the benefits found in virtualisation, management, storage, networking, access and information protection, virtual desktop protection etc..

I am going to run you through step by step how to download and install windows server and explain its benefits.

Firstly I downloaded windows server 2012 (or Windows server 8) from the 'DreamSpark' website as it is free for students of our University. It is the sixth release of the program.

System requirements:

Processor: Minimum: 1.4 GHz 64-bit processor
Ram: Minimum: 512 MB
Disk Space: Minimum: 32 GB

Once the file is downloaded run the install file.

Once the setup files are loaded, you will see the following screen. These can be changed to suit.

 
Then click "Install now".
 
 
In the following setup screen, you will see four options. Select Windows Server 2012 DataCenter Evaluation.
 
 
After you click Next from previous screen, Read the License terms, tick the "I accept the license terms" and click Next
 
 
 
Now It will ask you for the drive (or partition) you want to install it on.

 
 
Now once we picked our partition, clicking on next from previous screen will start the setup. This process might take a while.
 
Once the setup is done, it will restart and start your Windows Server 2012 for the first time. It will ask you then to set up a password for the Administrator user.
 
The setup will finalize your settings, might take a couple of minutes
 
 
Once you Log in, Windows Server 2012 will show the Server Manager
 
 
 

 
By using windows server it means that you dont have to buy as many licences for certain software that you may be using. Th4e software is simply licenced on one machine (maybe a virtual machine) and can be accessed from all other computers. Also data deduplication has saved companies more than 70 percent of their disc space by not having to store the same data on all machines.
 
 
 

 
 
 
 
 


Thursday, 13 March 2014

Graphics Cards & Displays

Displays

Flat panel PC monitors can receive either an analog signal, or a digital signal from a video card. There are various technologies that the monitor might have:
  • Liquid Crystal Display 
  • Plasma Display Panel - that uses a gas plasma display
  • ElectroLuminescent Display
  • Light Emitting Diode
The Quality of a display is measured in two areas,

  • Dot Pitch: this is the shortest distance between two dots of the same colour on the monitor, measured in millimeters (0.28mm is average).
  • Refresh rate: this is the amount of times per second that the screen is redrawn and is measured in Hz. The standard is 60Hz for VGA (Video Graphics Array).

The resolution of a screen is the measure of how many dots on the screen are addressable by software. These addressable dots are known as pixels. Most monitors have a resolution of 1024 x 768 or higher. The video card also has to be able to support the resolution as well as the monitor.

Graphics Cards

Graphics cards are known by various names, some more common than others:

  • Video cards
  • Video boards
  • Video display boards
  • Graphics boards
  • Graphics adapter cards
  • Graphics accelerators
The graphics card (the term I prefer) creates an image from data being passed to it and holds it. Nowadays it is in the form of a 'plug in card', but older technologies used specialised circuitry to carry out the same task, but far slower than the newer technologies today.

A typical display adapter will take digital data sent from an application, store that data in Video Random Access Memory (VRAM), use a digital to analog converter to convert the data to something that the monitor can display, then send the data to the monitor through a VGA cable.

VGA adapters do not fully support digital monitors however. This is why a new standard has been introduced being the Digital Video Interface (DVI). DVI keeps the data in digital form from PC to monitor which has the advantage of eliminating any degradation of the signal quality during the data conversion. A DVI monitor and DVI compliant monitor is required for this.

A graphics card receives data and instructions from the processor, processes the data and sends it on to the monitor. A graphics card relies on the bus it uses (which influences its speed and performance), and the amount of video RAM it either has or can support and the chip set on the card. A graphics card card be improved by having its own processor, this is known as a graphics accelerator.

A graphics accelerator has a processor that is specially designed to handle video and graphics. They are increasingly becoming far faster than the PC's CPU as they are required to calculate thousands of pixels maybe hundreds of time a second second. Imagine playing Call of Duty for example on a 32 inch screen. Roughly 1360 x 760 pixels, that's over a million pixels that have to be assigned a different colour multiple times a second. That Is why a GPU has to be so powerful. They are being used more and more frequently and have been used as a way to crack passwords because they are so fast at carrying out multiple calculations.

Main manufacturers of graphics cards include AMD, Nvidea and ARM.













Thursday, 6 March 2014

Hard Drives

Hard Drives

A hard drive is a series of magnetic disks that 'in essence' store a series of 1's and 0's that translate into different types of data.

A hard disk will be constantly spinning whilst the device is turned on, at a rate of around 7200 revolutions per minute. Obviously this is going to create a lot of heat so the cooling of the hard disc is crucial.

Properties of a hard drive include:

  • its Capacity
  • its expected lifespan
  • the drives access time
  • the drives seek time
  • the drives Latency

The capacity of a disc is calculated by the following:



(No. bytes per sector) x (no. sectors per track) x (no. tracks per cylinder) x (no. cylinders per disc)

A hard drives lifespan is referred to as its MTBF, or 'mean time before fail'.

The drives access time is derived from - Seek time + latency.

The drives seek time is the time it takes to locate the required cylinder on the disk.

The drives latency is the time it takes for the arm to move to the required cylinder on the disk.

An alternate hard drive to the disk drive is becoming more and more popular, the Solid State Disk (SSD).

Solid State Disk

A solid state disk has no moving parts within which has certain advantages on its predecessor. 
  • No moving parts mean less likely that the disc is damaged when being moved.
  • The seek time is reduced.
  • Less latency
  • Quieter with no noise at all.
The SSD is more expensive though.

Servers

A server needs a good architecture so that when a failure occurs, all the information on that server is not lost.

RAID (redundant array of inexpensive disks) is a data storage facility that uses multiple hard drives logically to eliminate the risk of data loss upon failure. A raid system has to have at least one RAID controller.

There are multiple RAID architectures that are named from 0 to 5.

RAID 0:




RAID 1:


From this architecture you can see that drive 1 (split into 6 blocks) is basically mirrored into drive 2, meaning that if one disk fails, the back up is still there with all the data. This was the case in the twin towers, one drive in each tower. But obviously as both towers went down, all the data was lost. Now companies put each disk in different geographical locations.

RAID 0 & 1

This architecture takes RAID 1 & 0 and utilises both.

There are RAIDS 2,3,4 and 5 but they aren't generally used.

Storing on a CD

  • Can hold up to 800 MB

Storing on a DVD

  • Can hold up to 17 GB

Storing on Blu-Ray

  • Can be dual layer, 25 GB per layer


Memory

Memory

Each different device will have different hardware, software and memory capabilities and restrictions. When designing a program for a certain device, for example a smart phone, research is crucial into the memory storage of the device, and how its interface relates to a specific browser.

Volatile Memory: Memory that you will lose once the device is powered down.

Non-volatile Memory: Memory that retains data once the power is shut off. Read only memories are the largest of these types.

More and more, browsers are starting to use non-volatile memory spaces to prevent annoying situations, for example, having to re-input user data upon a page refresh.

Random Access Memory (RAM)

Dynamic:

Data will leak even if power is on.
Based on capacitors.
Data must be refreshed about 1000 times a second.

Static (USB stick):

Will retain power as long as there is power.
Based on transistors.
Faster than DRAM but costs more.

Cache:

Fastest form of SRAM and also most expensive. Mainly utilised for holding most recent data.

Characteristics of RAM:

Capacity - The number of bytes that can be stored.
Speed - How quickly the data can be sent to the computer
Bandwidth - The rate at which the data can be sent to the computer
Technology - Typically DDR/DDR2/DDR3 soon to be entering the DDR4, as
the silicone is becoming smaller the voltage is also decreasing along the Buses.

When talking specifications, 50GB - the 'B' refers to eight bytes where as a specification of 100Mbps the 'b' refers to a byte.

All American standards are stated under IEEE. European standards are provided by ISO standards.



Monday, 17 February 2014

Virtualisation

Virtual Operating Sytems

Today I will be talking about how to use virtual box (free software), to create a virtual environment which you can install operating systems on.

Virtual box simply makes an exact copy of your pc, and allows you to operate it in exactly the same way as you would, without the risk of breaking your machine. A virtual environment allows the user to play with various operating systems along with any other settings without any fear of crashing the system, a broken virtual environment can simpy be erased and a new one installed.

Install oracle virtual box...


To install various operating systems the disc image of the OS will first be needed. Then simply click new and follow the instructions to create the virtual system. To install the OS onto the virtual system follow these instructions...

     1.  Settings - storage
     2.  host drive D - click the disc icon
     3.  choose a virtual cd/dvd - choose the OS disk image

Remember to choose a dynamic hard drive, this means that the virtual hard drive will grow as and when it is needed, otherwise it will crash when memory runs out!


 
 
Dont ask why I chose windows 8, I have no idea.



Benefits of Virtualisation

  1. Reduce carbon footprint - Migrating physical servers over to virtual machines and consolidating them onto far fewer physical servers means lowering monthly power and cooling costs in the data center.
  2. Improve disaster recovery -  by consolidating servers down to fewer physical machines in production, an organization can more easily create an affordable replication site.
  3. Help things move to the 'Cloud'.

How computers work

Processor

The main brain of a computer is the processor. The processor can carry out many thousands of calculations per second, whether it be what to calculate what colour a tree is going to be within a game from second to second, or what is required from various different user inputs etc..

Intel and AMD are the largest processor manufacturers. In general if spped is what you are looking for in your PC, Intel is the best option. If graphics are your main priority, go for AMD. Although there are so many models of each out there it is hard to say which is a 'better' option.

In computing, FLOPS (Floating point Operations Per second) is a measure of your pc's speed.


Most microprocessors today can do 4 FLOPs per clock cycle. Therefore, a single-core 2.5 GHz processor has a performance of roughly10 billion FLOPS, 10 billion operations per second(floating point). A floating point refers to an integer that programmers will use when compiling various applications.


The processor communicates with the memory through a set of wires called the bus. A 32 bit processor will have a 32 bit wide bus.
 
Two main manufacturers for processors are Intell and AMD

Bus

The address bus controls the address on memory of all information.
 
The control bus controls the information synchronising operation.
 
The data bus controls the data and instructions moving between. 

 
 

Boot


The term boot refers to the computer pulling itself up from its boot straps. It is the start to finsh loading process of a computer.
 
A typical boot sequence:
 
Location of CPU and memory:
 

 

A computer will run several tests as it is 'booting'. If any errors are detected with the cpu, timer or memory then an error will be reported to the user via varying beeps, and the boot process may be aborted to prevent further damage to the system, depending on the severity of the error. This is known as the 'Power on self test' (POST).

The basic input output system (BIOS) holds basic system configurations which include boot sequence details. The bios loads the bootstrap loader from master boot record on the disk.

The master boot record shows where the operating system is in memory. If it can not be found then the boot process will fail.

Interrupt handlers 

When a  processor is working to nearly capacity, say if it is calculating the next screen of an online multiplayer game, how do we get its attention when we want to alter tasks? This is where interrupt handlers come in handy. An interrupt is something like pressing the escape key to pause. An interrupt overpowers all processes and sends a request to the processor. The processor in turn listens for instructions. These come in the form of an interrupt handler, which is a piece of code which directs the processor to the correct destination - was it the keyboard, mouse, hard-drive creating the interupt? Then based on the destination it will run the routine process for the particular action.

Direct memory access

DMA allows for more efficient system operation by allowing data transfer to bypass the processor. The processor will initially set up the direct memory access, and then it is free to carry out other duties.

Typical PC architecture: